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 Post subject: Resizing and options.
Unread postPosted: Thu Apr 02, 2009 2:00 pm 
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Honorary Virtual Ranger
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Joined: Fri Jan 14, 2005 5:42 pm
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Location: Red sand, why do I keep thinking of red sand?
A thing that I noticed is that many people don't have their options set right when resizing. One of them is DPI, Dots Per Inch, a measure of printing resolution. Now have a look at these two photos:

Image

Image

Do you see a difference? :hmz: Those are a little small, lets give you two larger ones. As link only, don't want upset those with caps or modems:
option 1 and option 2.

No difference you say? Well there is! The first of the visible photos is 82 KB, the second 51 KB. With the links it's even worse, 148 KB versus 103 KB.
Now 30 to 40 KB may not seem to be a lot, but with a tripreport with dozens of photos? Or on your site? It adds up!

How did I manage that? Easy, by lowering the DPI set in the photo. And not with an expensive program either, but the totally free Irfanview.
If you download the first of the photos, open it in Irfanview and press "I" on your keyboard you'll get this screen:
Image
You'll see that in the red box it says 240x240 DPI. I just edited that to 1x1 and pressed change. Then saved it, and that's the second photo you see.
There is a quicker way to do it, you need to resize your photos anyway before uploading. have a look at this:

Image
In red is the option where you can set the DPI.

Have fun with it, I used it on nigh to 1000 photos (for the competition) and that saved me many, many MB's.

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 Post subject: Re: Resizing and options.
Unread postPosted: Thu Apr 02, 2009 3:22 pm 
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Joined: Wed Jul 27, 2005 9:21 pm
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Location: Port Elizabeth
:huh:

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 Post subject: Re: Resizing and options.
Unread postPosted: Thu Apr 02, 2009 4:03 pm 
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Honorary Virtual Ranger
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Location: Red sand, why do I keep thinking of red sand?
The filesize is way smaller?

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Arriving currently: The photos from our trip! Overhere! :yaya:

Feel free to use any of these additional letters to correct the spelling of words found in the above post: a-e-t-n-d-i-o-s-m-l-u-y-h-c


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 Post subject: Re: Resizing and options.
Unread postPosted: Sat Apr 04, 2009 7:40 am 
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Junior Virtual Ranger
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Joined: Tue Jun 05, 2007 6:22 pm
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Location: Lowveld - Near Kruger!
DuQues,

The links you show (option 1 and option 2) link to exactly the same file (crocus_large_1.jpg). So opening the two photos and right-click/properties, both show 103 kb size. Did you link the wrong file?

Also, it seems that this trick only works with Irfanview. I use Lightroom or Photoshop to resize, and tried this trick, but the files came out exactly the same size. I do not have Irfanview, so could not verify this.

Based on my research, the final size of jpg images is ONLY determined by the photo size (number of pixels) and the compression ratio (%). The DPI setting is only used when printing the photo.

Do I miss something here?


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